Today was Charter Day in Pennsylvania. In honor of the day William Penn got the Charter for Pennsylvania from the king, entrance to all state historical sites is free. This year we decided to see the Cornwall Iron Furnace. We had often passed through Cornwall but never toured the furnace. Now we have finally seen it and it is impressive. It is the only surviving intact charcoal cold blast furnace in the Western Hemisphere.
Cornwall Iron Furnace was in operation from 1742 to 1883. Peter Grubb started mining here in 1730 and established the furnace in 1742. He named it Cornwall for his father's birthplace in England. In the mid-eighteenth century Cornwall's plantation totaled 10,000 acres and contained industrial, residential, and agricultural activities.
When Peter Grubb died in 1754, the property passed to his sons, Curtis and Peter. They sold out to Robert Coleman in 1798. He was so successful he became one of Pennsylvania's first millionaires. This furnace building was constructed in the mid-1800s when the furnace was remodeled and enlarged by Coleman.
Charcoal, iron ore and limestone were layered in the furnace in the charging room on the upper level. It would have been about 115 degrees in this room. The materials were pushed in these hand carts and dumped into the hole which was the top of the furnace. The hole is behind the protective grate at the back of the room. It was covered with a glass panel so we could see to the bottom. It's a long way to the bottom of the furnace!
The casting room is at the bottom of the furnace.
Molten iron was pink when it ran out the bottom of the furnace into the trough on the floor. It flowed into a double row of ditches dug in the sand where they cooled and hardened. The iron bars were called "pigs." Boys about eight or nine years old carried out the waste material. The temperature in this room was about 156. They worked twelve-hour shifts around the clock seven days a week. Iron workers often did not live beyond the age of forty. No wonder!
During the Revolutionary War, the furnace produced cannon balls. Each one weighs twelve pounds. This is a pile of cannon balls which were produced at Cornwall.
The furnace was heated to 3000 degrees and fanned by pumping air into it. Originally, the air was pumped by water power but in 1841 a steam engine was installed to run the huge 24-ft. wheel. It was impossible to get the whole wheel in one picture. It was turning slowly for demonstration purposes but when the furnace was in operation it turned at the speed of one revolution every 15 seconds.
Originally the top of the furnace was open. The glow of the fire could be seen for five miles and the sound of its roaring could be heard a mile away. This was a hot, noisy, dirty place to work, but very profitable business for the ironmaster. Perhaps some of that was due to the fact that he used some slave labor and indentured servants. In addition to the men who worked in the furnace, there were others who lived in the woods and produced the charcoal to fire the furnace and others who worked in the quarry nearby. An acre of wood was needed each day to keep the furnace going. It operated continuously for eleven months. Then it was shut down to replace the bricks which line the inside of the furnace.
Bethlehem Steel acquired the mine between 1916 and 1922. It began to flood during Hurricane Agnes in 1972 and today is filled with water. Approximately 106 million tons of iron ore and over 82 minerals were extracted from the mine between 1730 and 1973. The depth of the open pit is about 500 feet below the surface.